UPSC 2010: Due to their extensive rice cultivation, some regions may be contributing to global warming. To what possible reason/reasons is this attributable? 1. The anaerobic conditions associated with rice cultivation cause the emission of methane. 2. When nitrogen based fertilizers are used, nitrous oxide is emitted from the cultivated soil. Which of the statements given above is/are correct?

Continuously flooded rice paddies create anaerobic soil conditions that favour methanogenic bacteria, so rice cultivation is a major anthropogenic source of CH₄. In contrast, nitrous-oxide (N₂O) peaks arise mainly from aerobic nitrification/denitrification after heavy N-fertilizer use in upland soils; under the strictly anaerobic conditions of flooded paddy this pathway is limited, so large N₂O emissions are not characteristic. Hence only statement 1 is correct([iasexamportal.com](https://iasexamportal.com/Answer-Key/General-Studies-Solution-CSP-2010)).